{"id":135288,"date":"2026-07-20T09:31:43","date_gmt":"2026-07-20T03:31:43","guid":{"rendered":"https:\/\/rcl-radio.ru\/?p=135288"},"modified":"2026-07-20T09:31:43","modified_gmt":"2026-07-20T03:31:43","slug":"%d0%be%d0%b1%d0%bb%d0%b0%d1%81%d1%82%d1%8c-%d0%b2%d0%b8%d0%b4%d0%b8%d0%bc%d0%be%d1%81%d1%82%d0%b8-%d0%b2-javascript-%d1%80%d0%b0%d0%b7%d0%b1%d0%b8%d1%80%d0%b0%d0%b5%d0%bc-var-let-%d0%b8-const-%d0%bd","status":"publish","type":"post","link":"https:\/\/rcl-radio.ru\/?p=135288","title":{"rendered":"\u041e\u0431\u043b\u0430\u0441\u0442\u044c \u0432\u0438\u0434\u0438\u043c\u043e\u0441\u0442\u0438 \u0432 JavaScript: \u0440\u0430\u0437\u0431\u0438\u0440\u0430\u0435\u043c var, let \u0438 const \u043d\u0430 \u043f\u0440\u0438\u043c\u0435\u0440\u0430\u0445 (JavaScript)"},"content":{"rendered":"<p>\u041e\u0431\u043b\u0430\u0441\u0442\u044c \u0432\u0438\u0434\u0438\u043c\u043e\u0441\u0442\u0438 \u0433\u043e\u0432\u043e\u0440\u0438\u0442, \u0433\u0434\u0435 \u0432 \u043a\u043e\u0434\u0435 \u043f\u0435\u0440\u0435\u043c\u0435\u043d\u043d\u0430\u044f \u00ab\u0436\u0438\u0432\u0451\u0442\u00bb \u0438 \u0433\u0434\u0435 \u0435\u0451 \u043c\u043e\u0436\u043d\u043e \u0438\u0441\u043f\u043e\u043b\u044c\u0437\u043e\u0432\u0430\u0442\u044c. \u0415\u0441\u043b\u0438 \u043d\u0435 \u0443\u0447\u0438\u0442\u044b\u0432\u0430\u0442\u044c \u043f\u0440\u0430\u0432\u0438\u043b\u0430 \u0434\u043b\u044f <code class=\"CodeInlined\">var<\/code>\/<code class=\"CodeInlined\">let<\/code>\/<code class=\"CodeInlined\">const<\/code>, \u043a\u043e\u0434 \u0431\u0443\u0434\u0435\u0442 \u0432\u044b\u0434\u0430\u0432\u0430\u0442\u044c \u0441\u0442\u0440\u0430\u043d\u043d\u044b\u0435 \u0437\u043d\u0430\u0447\u0435\u043d\u0438\u044f \u0438\u043b\u0438 \u043f\u0430\u0434\u0430\u0442\u044c \u0441 \u043e\u0448\u0438\u0431\u043a\u0430\u043c\u0438. \u0414\u0430\u043b\u044c\u0448\u0435 \u2014 \u0442\u043e\u043b\u044c\u043a\u043e \u0444\u0430\u043a\u0442\u044b \u0438 \u043f\u0440\u0438\u043c\u0435\u0440\u044b, \u043a\u043e\u0442\u043e\u0440\u044b\u0435 \u043c\u043e\u0436\u043d\u043e \u0441\u0440\u0430\u0437\u0443 \u043f\u0440\u043e\u0432\u0435\u0440\u0438\u0442\u044c.<\/p>\n<hr \/>\n<h2><code class=\"CodeInlined\">var<\/code>: \u0436\u0438\u0432\u0451\u0442 \u043f\u043e \u0444\u0443\u043d\u043a\u0446\u0438\u0438, \u0432\u0441\u043f\u043b\u044b\u0432\u0430\u0435\u0442, \u0440\u0430\u0437\u0440\u0435\u0448\u0430\u0435\u0442 \u043f\u043e\u0432\u0442\u043e\u0440<\/h2>\n<p><strong>\u0427\u0442\u043e \u044d\u0442\u043e \u0437\u043d\u0430\u0447\u0438\u0442 \u043d\u0430 \u043f\u0440\u0430\u043a\u0442\u0438\u043a\u0435:<\/strong><\/p>\n<ul>\n<li data-value=\"\" data-shift=\"0\">\u0412\u0438\u0434\u0435\u043d \u0432\u043e \u0432\u0441\u0435\u0439 \u0444\u0443\u043d\u043a\u0446\u0438\u0438, \u0431\u043b\u043e\u043a <code class=\"CodeInlined\">{}<\/code> \u0435\u0433\u043e \u043d\u0435 \u043e\u0433\u0440\u0430\u043d\u0438\u0447\u0438\u0432\u0430\u0435\u0442.<\/li>\n<li data-value=\"\" data-shift=\"0\">\u041e\u0431\u044a\u044f\u0432\u043b\u0435\u043d\u0438\u0435 \u0432\u0441\u043f\u043b\u044b\u0432\u0430\u0435\u0442 \u043d\u0430\u0432\u0435\u0440\u0445 \u0444\u0443\u043d\u043a\u0446\u0438\u0438, \u043d\u043e \u0434\u043e \u043f\u0440\u0438\u0441\u0432\u0430\u0438\u0432\u0430\u043d\u0438\u044f \u0437\u043d\u0430\u0447\u0435\u043d\u0438\u0435 \u0431\u0443\u0434\u0435\u0442 <code class=\"CodeInlined\">undefined<\/code>.<\/li>\n<li data-value=\"\" data-shift=\"0\">\u041c\u043e\u0436\u043d\u043e \u0434\u0432\u0430 \u0440\u0430\u0437\u0430 \u043d\u0430\u043f\u0438\u0441\u0430\u0442\u044c <code class=\"CodeInlined\">var x<\/code> \u0432 \u043e\u0434\u043d\u043e\u0439 \u043e\u0431\u043b\u0430\u0441\u0442\u0438 \u2014 \u043e\u0448\u0438\u0431\u043a\u0438 \u043d\u0435 \u0431\u0443\u0434\u0435\u0442.<\/li>\n<\/ul>\n<p><strong>\u041f\u0440\u0438\u043c\u0435\u0440 1: <code class=\"CodeInlined\">var<\/code> \u0432\u043d\u0443\u0442\u0440\u0438 <code class=\"CodeInlined\">if<\/code> \u2014 \u0432\u0438\u0434\u0435\u043d \u0441\u043d\u0430\u0440\u0443\u0436\u0438<\/strong><\/p>\n<div class=\"CodeBlock CodeBlock_overflow_visible CodeBlock_highlight\">\n<div class=\"CodeBlock-StickyWrapper\">\n<div class=\"CodeBlock-Header\">\n<div class=\"CodeBlock-HeaderTitle\">js<\/div>\n<pre class=\"actionscript\" style=\"font-family: monospace; font-size: 14px;\"><span style=\"color: #000000; font-weight: bold;\">function<\/span> demoVar<span style=\"color: #66cc66;\">(<\/span><span style=\"color: #66cc66;\">)<\/span> <span style=\"color: #66cc66;\">{<\/span>\r\n  <span style=\"color: #b1b100;\">if<\/span> <span style=\"color: #66cc66;\">(<\/span><span style=\"color: #000000; font-weight: bold;\">true<\/span><span style=\"color: #66cc66;\">)<\/span> <span style=\"color: #66cc66;\">{<\/span>\r\n    <span style=\"color: #000000; font-weight: bold;\">var<\/span> x = <span style=\"color: #cc66cc;\">10<\/span>;\r\n  <span style=\"color: #66cc66;\">}<\/span>\r\n  console.<span style=\"color: #0066cc;\">log<\/span><span style=\"color: #66cc66;\">(<\/span>x<span style=\"color: #66cc66;\">)<\/span>; <span style=\"color: #808080; font-style: italic;\">\/\/ 10<\/span>\r\n<span style=\"color: #66cc66;\">}<\/span>\r\ndemoVar<span style=\"color: #66cc66;\">(<\/span><span style=\"color: #66cc66;\">)<\/span>;<\/pre>\n<\/div>\n<\/div>\n<\/div>\n<p>\u0417\u0434\u0435\u0441\u044c <code class=\"CodeInlined\">x<\/code> \u0434\u043e\u0441\u0442\u0443\u043f\u0435\u043d \u043f\u043e\u0441\u043b\u0435 <code class=\"CodeInlined\">if<\/code>, \u043f\u043e\u0442\u043e\u043c\u0443 \u0447\u0442\u043e \u0434\u043b\u044f <code class=\"CodeInlined\">var<\/code> \u0431\u043b\u043e\u043a \u043d\u0435 \u0441\u043e\u0437\u0434\u0430\u0451\u0442 \u043e\u0442\u0434\u0435\u043b\u044c\u043d\u0443\u044e \u043e\u0431\u043b\u0430\u0441\u0442\u044c.<\/p>\n<p><strong>\u041f\u0440\u0438\u043c\u0435\u0440 2: \u0446\u0438\u043a\u043b \u0441 <code class=\"CodeInlined\">var<\/code> \u2014 \u0441\u0447\u0451\u0442\u0447\u0438\u043a \u043e\u0441\u0442\u0430\u0451\u0442\u0441\u044f \u043f\u043e\u0441\u043b\u0435 \u0446\u0438\u043a\u043b\u0430<\/strong><\/p>\n<div class=\"CodeBlock CodeBlock_overflow_visible CodeBlock_highlight\">\n<div class=\"CodeBlock-StickyWrapper\">\n<div class=\"CodeBlock-Header\">\n<div class=\"CodeBlock-HeaderTitle\">js<\/div>\n<pre class=\"actionscript\" style=\"font-family: monospace; font-size: 14px;\"><span style=\"color: #b1b100;\">for<\/span> <span style=\"color: #66cc66;\">(<\/span><span style=\"color: #000000; font-weight: bold;\">var<\/span> i = <span style=\"color: #cc66cc;\">0<\/span>; i <span style=\"color: #66cc66;\">&lt;<\/span> <span style=\"color: #cc66cc;\">3<\/span>; i++<span style=\"color: #66cc66;\">)<\/span> <span style=\"color: #66cc66;\">{<\/span><span style=\"color: #66cc66;\">}<\/span>\r\nconsole.<span style=\"color: #0066cc;\">log<\/span><span style=\"color: #66cc66;\">(<\/span>i<span style=\"color: #66cc66;\">)<\/span>; <span style=\"color: #808080; font-style: italic;\">\/\/ 3<\/span><\/pre>\n<\/div>\n<\/div>\n<\/div>\n<p>\u041f\u0435\u0440\u0435\u043c\u0435\u043d\u043d\u0430\u044f <code class=\"CodeInlined\">i<\/code> \u043f\u0440\u043e\u0434\u043e\u043b\u0436\u0430\u0435\u0442 \u0441\u0443\u0449\u0435\u0441\u0442\u0432\u043e\u0432\u0430\u0442\u044c \u043f\u043e\u0441\u043b\u0435 \u0446\u0438\u043a\u043b\u0430. \u042d\u0442\u043e \u043b\u0435\u0433\u043a\u043e \u043b\u043e\u043c\u0430\u0435\u0442 \u043b\u043e\u0433\u0438\u043a\u0443, \u0435\u0441\u043b\u0438 \u0434\u0430\u043b\u044c\u0448\u0435 \u0432 \u043a\u043e\u0434\u0435 \u0435\u0441\u0442\u044c \u0441\u0432\u043e\u044f <code class=\"CodeInlined\">i<\/code>.<\/p>\n<p><strong>\u041f\u0440\u0438\u043c\u0435\u0440 3: \u043e\u0431\u0440\u0430\u0449\u0435\u043d\u0438\u0435 \u0434\u043e \u043e\u0431\u044a\u044f\u0432\u043b\u0435\u043d\u0438\u044f \u2192 <code class=\"CodeInlined\">undefined<\/code><\/strong><\/p>\n<div class=\"CodeBlock CodeBlock_overflow_visible CodeBlock_highlight\">\n<div class=\"CodeBlock-StickyWrapper\">\n<div class=\"CodeBlock-Header\">\n<div class=\"CodeBlock-HeaderTitle\">js<\/div>\n<pre class=\"actionscript\" style=\"font-family: monospace; font-size: 14px;\">console.<span style=\"color: #0066cc;\">log<\/span><span style=\"color: #66cc66;\">(<\/span>z<span style=\"color: #66cc66;\">)<\/span>; <span style=\"color: #808080; font-style: italic;\">\/\/ undefined<\/span>\r\n<span style=\"color: #000000; font-weight: bold;\">var<\/span> z = <span style=\"color: #cc66cc;\">5<\/span>;<\/pre>\n<\/div>\n<\/div>\n<\/div>\n<p>\u0424\u0430\u043a\u0442\u0438\u0447\u0435\u0441\u043a\u0438 JS \u043e\u0431\u0440\u0430\u0431\u0430\u0442\u044b\u0432\u0430\u0435\u0442 \u044d\u0442\u043e \u0442\u0430\u043a:<\/p>\n<div class=\"CodeBlock CodeBlock_overflow_visible CodeBlock_highlight\">\n<div class=\"CodeBlock-StickyWrapper\">\n<div class=\"CodeBlock-Header\">\n<div class=\"CodeBlock-HeaderTitle\">js<\/div>\n<pre class=\"actionscript\" style=\"font-family: monospace; font-size: 14px;\"><span style=\"color: #000000; font-weight: bold;\">var<\/span> z;\r\nconsole.<span style=\"color: #0066cc;\">log<\/span><span style=\"color: #66cc66;\">(<\/span>z<span style=\"color: #66cc66;\">)<\/span>; <span style=\"color: #808080; font-style: italic;\">\/\/ undefined<\/span>\r\nz = <span style=\"color: #cc66cc;\">5<\/span>;<\/pre>\n<\/div>\n<\/div>\n<\/div>\n<p>\u0418\u0437\u2011\u0437\u0430 \u044d\u0442\u043e\u0433\u043e \u0431\u044b\u0432\u0430\u0435\u0442 \u0442\u0440\u0443\u0434\u043d\u043e \u043f\u043e\u043d\u044f\u0442\u044c, \u043f\u043e\u0447\u0435\u043c\u0443 \u0437\u043d\u0430\u0447\u0435\u043d\u0438\u0435 \u043d\u0435 \u0442\u043e.<\/p>\n<p><strong>\u041f\u0440\u0438\u043c\u0435\u0440 4: \u043f\u043e\u0432\u0442\u043e\u0440\u043d\u043e\u0435 \u043e\u0431\u044a\u044f\u0432\u043b\u0435\u043d\u0438\u0435 <code class=\"CodeInlined\">var<\/code> \u0431\u0435\u0437 \u043e\u0448\u0438\u0431\u043a\u0438<\/strong><\/p>\n<div class=\"CodeBlock CodeBlock_overflow_visible CodeBlock_highlight\">\n<div class=\"CodeBlock-StickyWrapper\">\n<div class=\"CodeBlock-Header\">\n<div class=\"CodeBlock-HeaderTitle\">js<\/div>\n<pre class=\"actionscript\" style=\"font-family: monospace; font-size: 14px;\"><span style=\"color: #000000; font-weight: bold;\">var<\/span> a = <span style=\"color: #cc66cc;\">1<\/span>;\r\n<span style=\"color: #000000; font-weight: bold;\">var<\/span> a = <span style=\"color: #cc66cc;\">2<\/span>;\r\nconsole.<span style=\"color: #0066cc;\">log<\/span><span style=\"color: #66cc66;\">(<\/span>a<span style=\"color: #66cc66;\">)<\/span>; <span style=\"color: #808080; font-style: italic;\">\/\/ 2<\/span><\/pre>\n<\/div>\n<\/div>\n<\/div>\n<p>\u0412 \u0431\u043e\u043b\u044c\u0448\u043e\u043c \u0444\u0430\u0439\u043b\u0435 \u043b\u0435\u0433\u043a\u043e \u0441\u043b\u0443\u0447\u0430\u0439\u043d\u043e \u043f\u0440\u043e\u0434\u0443\u0431\u043b\u0438\u0440\u043e\u0432\u0430\u0442\u044c \u0438\u043c\u044f \u0438 \u043d\u0435\u0437\u0430\u043c\u0435\u0442\u043d\u043e \u043f\u043e\u043c\u0435\u043d\u044f\u0442\u044c \u0437\u043d\u0430\u0447\u0435\u043d\u0438\u0435.<\/p>\n<hr \/>\n<h2><code class=\"CodeInlined\">let<\/code>: \u0436\u0438\u0432\u0451\u0442 \u0442\u043e\u043b\u044c\u043a\u043e \u0432 \u0431\u043b\u043e\u043a\u0435, \u043d\u0435\u043b\u044c\u0437\u044f \u043f\u043e\u0432\u0442\u043e\u0440\u043d\u043e \u043e\u0431\u044a\u044f\u0432\u0438\u0442\u044c, \u0434\u043e \u043e\u0431\u044a\u044f\u0432\u043b\u0435\u043d\u0438\u044f \u2014 \u043e\u0448\u0438\u0431\u043a\u0430<\/h2>\n<p><strong>\u0427\u0442\u043e \u044d\u0442\u043e \u0437\u043d\u0430\u0447\u0438\u0442 \u043d\u0430 \u043f\u0440\u0430\u043a\u0442\u0438\u043a\u0435:<\/strong><\/p>\n<ul>\n<li data-value=\"\" data-shift=\"0\">\u041e\u0431\u043b\u0430\u0441\u0442\u044c \u2014 \u0431\u043b\u043e\u043a <code class=\"CodeInlined\">{}<\/code>: <code class=\"CodeInlined\">if<\/code>, <code class=\"CodeInlined\">for<\/code>, <code class=\"CodeInlined\">while<\/code>, \u043b\u044e\u0431\u044b\u0435 \u0444\u0438\u0433\u0443\u0440\u043d\u044b\u0435 \u0441\u043a\u043e\u0431\u043a\u0438.<\/li>\n<li data-value=\"\" data-shift=\"0\">\u041d\u0435\u043b\u044c\u0437\u044f \u0434\u0432\u0430 \u0440\u0430\u0437\u0430 \u043e\u0431\u044a\u044f\u0432\u0438\u0442\u044c <code class=\"CodeInlined\">let x<\/code> \u0432 \u043e\u0434\u043d\u043e\u043c \u0431\u043b\u043e\u043a\u0435 \u2014 \u0431\u0443\u0434\u0435\u0442 \u043e\u0448\u0438\u0431\u043a\u0430.<\/li>\n<li data-value=\"\" data-shift=\"0\">\u0414\u043e \u0441\u0442\u0440\u043e\u043a\u0438 \u043e\u0431\u044a\u044f\u0432\u043b\u0435\u043d\u0438\u044f \u043f\u0435\u0440\u0435\u043c\u0435\u043d\u043d\u0430\u044f \u043d\u0435\u0434\u043e\u0441\u0442\u0443\u043f\u043d\u0430: \u043f\u043e\u043f\u044b\u0442\u043a\u0430 \u043f\u0440\u043e\u0447\u0438\u0442\u0430\u0442\u044c \u0432\u044b\u0437\u043e\u0432\u0435\u0442 <code class=\"CodeInlined\">ReferenceError<\/code>, \u0430 \u043d\u0435 <code class=\"CodeInlined\">undefined<\/code>.<\/li>\n<\/ul>\n<p><strong>\u041f\u0440\u0438\u043c\u0435\u0440 1: <code class=\"CodeInlined\">let<\/code> \u0432\u043d\u0443\u0442\u0440\u0438 <code class=\"CodeInlined\">if<\/code> \u2014 \u0441\u043d\u0430\u0440\u0443\u0436\u0438 \u0435\u0433\u043e \u043d\u0435\u0442<\/strong><\/p>\n<div class=\"CodeBlock CodeBlock_overflow_visible CodeBlock_highlight\">\n<div class=\"CodeBlock-StickyWrapper\">\n<div class=\"CodeBlock-Header\">\n<div class=\"CodeBlock-HeaderTitle\">js<\/div>\n<pre class=\"actionscript\" style=\"font-family: monospace; font-size: 14px;\"><span style=\"color: #000000; font-weight: bold;\">function<\/span> demoLet<span style=\"color: #66cc66;\">(<\/span><span style=\"color: #66cc66;\">)<\/span> <span style=\"color: #66cc66;\">{<\/span>\r\n  <span style=\"color: #b1b100;\">if<\/span> <span style=\"color: #66cc66;\">(<\/span><span style=\"color: #000000; font-weight: bold;\">true<\/span><span style=\"color: #66cc66;\">)<\/span> <span style=\"color: #66cc66;\">{<\/span>\r\n    let y = <span style=\"color: #cc66cc;\">20<\/span>;\r\n  <span style=\"color: #66cc66;\">}<\/span>\r\n  <span style=\"color: #808080; font-style: italic;\">\/\/ console.log(y); \/\/ ReferenceError: y is not defined<\/span>\r\n<span style=\"color: #66cc66;\">}<\/span>\r\ndemoLet<span style=\"color: #66cc66;\">(<\/span><span style=\"color: #66cc66;\">)<\/span>;<\/pre>\n<\/div>\n<\/div>\n<\/div>\n<p>\u0411\u043b\u043e\u043a \u0440\u0435\u0430\u043b\u044c\u043d\u043e \u0438\u0437\u043e\u043b\u0438\u0440\u0443\u0435\u0442 \u043f\u0435\u0440\u0435\u043c\u0435\u043d\u043d\u0443\u044e.<\/p>\n<p><strong>\u041f\u0440\u0438\u043c\u0435\u0440 2: \u0446\u0438\u043a\u043b \u0441 <code class=\"CodeInlined\">let<\/code> \u2014 \u0441\u0447\u0451\u0442\u0447\u0438\u043a \u043d\u0435 \u0432\u0438\u0434\u0435\u043d \u043f\u043e\u0441\u043b\u0435 \u0446\u0438\u043a\u043b\u0430<\/strong><\/p>\n<div class=\"CodeBlock CodeBlock_overflow_visible CodeBlock_highlight\">\n<div class=\"CodeBlock-StickyWrapper\">\n<div class=\"CodeBlock-Header\">\n<div class=\"CodeBlock-HeaderTitle\">js<\/div>\n<pre class=\"actionscript\" style=\"font-family: monospace; font-size: 14px;\"><span style=\"color: #b1b100;\">for<\/span> <span style=\"color: #66cc66;\">(<\/span>let j = <span style=\"color: #cc66cc;\">0<\/span>; j <span style=\"color: #66cc66;\">&lt;<\/span> <span style=\"color: #cc66cc;\">3<\/span>; j++<span style=\"color: #66cc66;\">)<\/span> <span style=\"color: #66cc66;\">{<\/span><span style=\"color: #66cc66;\">}<\/span>\r\n<span style=\"color: #808080; font-style: italic;\">\/\/ console.log(j); \/\/ ReferenceError: j is not defined<\/span><\/pre>\n<\/div>\n<\/div>\n<\/div>\n<p>\u0426\u0438\u043a\u043b \u043d\u0435 \u00ab\u043e\u0441\u0442\u0430\u0432\u043b\u044f\u0435\u0442 \u043c\u0443\u0441\u043e\u0440\u00bb \u0441\u043d\u0430\u0440\u0443\u0436\u0438.<\/p>\n<p><strong>\u041f\u0440\u0438\u043c\u0435\u0440 3: \u043d\u0435\u043b\u044c\u0437\u044f \u0434\u0432\u0430\u0436\u0434\u044b \u043e\u0431\u044a\u044f\u0432\u0438\u0442\u044c <code class=\"CodeInlined\">let<\/code> \u0432 \u043e\u0434\u043d\u043e\u043c \u0431\u043b\u043e\u043a\u0435<\/strong><\/p>\n<div class=\"CodeBlock CodeBlock_overflow_visible CodeBlock_highlight\">\n<div class=\"CodeBlock-StickyWrapper\">\n<div class=\"CodeBlock-Header\">\n<div class=\"CodeBlock-HeaderTitle\">js<\/div>\n<pre class=\"actionscript\" style=\"font-family: monospace; font-size: 14px;\">let b = <span style=\"color: #cc66cc;\">1<\/span>;\r\n<span style=\"color: #808080; font-style: italic;\">\/\/ let b = 2; \/\/ SyntaxError: Identifier 'b' has already been declared<\/span><\/pre>\n<\/div>\n<\/div>\n<\/div>\n<p>\u042d\u0442\u043e \u0437\u0430\u0449\u0438\u0449\u0430\u0435\u0442 \u043e\u0442 \u0441\u043b\u0443\u0447\u0430\u0439\u043d\u044b\u0445 \u043f\u0435\u0440\u0435\u0437\u0430\u043f\u0438\u0441\u0435\u0439.<\/p>\n<p><strong>\u041f\u0440\u0438\u043c\u0435\u0440 4: \u0434\u043e \u043e\u0431\u044a\u044f\u0432\u043b\u0435\u043d\u0438\u044f \u0442\u0440\u043e\u0433\u0430\u0442\u044c \u043d\u0435\u043b\u044c\u0437\u044f<\/strong><\/p>\n<div class=\"CodeBlock CodeBlock_overflow_visible CodeBlock_highlight\">\n<div class=\"CodeBlock-StickyWrapper\">\n<div class=\"CodeBlock-Header\">\n<div class=\"CodeBlock-HeaderTitle\">js<\/div>\n<pre class=\"actionscript\" style=\"font-family: monospace; font-size: 14px;\"><span style=\"color: #808080; font-style: italic;\">\/\/ console.log(c); \/\/ ReferenceError: Cannot access 'c' before initialization<\/span>\r\nlet c = <span style=\"color: #cc66cc;\">3<\/span>;<\/pre>\n<\/div>\n<\/div>\n<\/div>\n<p>\u0415\u0441\u043b\u0438 \u043f\u043e\u0440\u044f\u0434\u043e\u043a \u043f\u0435\u0440\u0435\u043f\u0443\u0442\u0430\u043d \u2014 \u0441\u0440\u0430\u0437\u0443 \u043e\u0448\u0438\u0431\u043a\u0430, \u0435\u0451 \u043f\u0440\u043e\u0449\u0435 \u0437\u0430\u043c\u0435\u0442\u0438\u0442\u044c.<\/p>\n<hr \/>\n<h2><code class=\"CodeInlined\">const<\/code>: \u043a\u0430\u043a <code class=\"CodeInlined\">let<\/code>, \u043d\u043e \u043d\u0435\u043b\u044c\u0437\u044f \u043f\u0435\u0440\u0435\u043d\u0430\u0437\u043d\u0430\u0447\u0438\u0442\u044c<\/h2>\n<p><strong>\u0427\u0442\u043e \u044d\u0442\u043e \u0437\u043d\u0430\u0447\u0438\u0442 \u043d\u0430 \u043f\u0440\u0430\u043a\u0442\u0438\u043a\u0435:<\/strong><\/p>\n<ul>\n<li data-value=\"\" data-shift=\"0\">\u041f\u043e \u043e\u0431\u043b\u0430\u0441\u0442\u0438 \u0432\u0438\u0434\u0438\u043c\u043e\u0441\u0442\u0438 \u0432\u0435\u0434\u0451\u0442 \u0441\u0435\u0431\u044f \u043a\u0430\u043a <code class=\"CodeInlined\">let<\/code> (\u0431\u043b\u043e\u043a <code class=\"CodeInlined\">{}<\/code>).<\/li>\n<li data-value=\"\" data-shift=\"0\">\u041d\u0435\u043b\u044c\u0437\u044f \u0441\u0434\u0435\u043b\u0430\u0442\u044c <code class=\"CodeInlined\">const x = ...<\/code> \u0438 \u043f\u043e\u0442\u043e\u043c <code class=\"CodeInlined\">x = ...<\/code>.<\/li>\n<li data-value=\"\" data-shift=\"0\">\u0414\u043b\u044f \u043e\u0431\u044a\u0435\u043a\u0442\u043e\u0432 \u0438 \u043c\u0430\u0441\u0441\u0438\u0432\u043e\u0432 \u043c\u043e\u0436\u043d\u043e \u043c\u0435\u043d\u044f\u0442\u044c \u0441\u0432\u043e\u0439\u0441\u0442\u0432\u0430\/\u044d\u043b\u0435\u043c\u0435\u043d\u0442\u044b, \u043d\u043e \u043d\u0435\u043b\u044c\u0437\u044f \u043f\u0440\u0438\u0441\u0432\u043e\u0438\u0442\u044c \u043d\u043e\u0432\u0443\u044e \u0441\u0441\u044b\u043b\u043a\u0443.<\/li>\n<\/ul>\n<p><strong>\u041f\u0440\u0438\u043c\u0435\u0440 1: \u043d\u0435\u043b\u044c\u0437\u044f \u043f\u0435\u0440\u0435\u043d\u0430\u0437\u043d\u0430\u0447\u0438\u0442\u044c <code class=\"CodeInlined\">const<\/code><\/strong><\/p>\n<div class=\"CodeBlock CodeBlock_overflow_visible CodeBlock_highlight\">\n<div class=\"CodeBlock-StickyWrapper\">\n<div class=\"CodeBlock-Header\">\n<div class=\"CodeBlock-HeaderTitle\">js<\/div>\n<pre class=\"actionscript\" style=\"font-family: monospace; font-size: 14px;\">const d = <span style=\"color: #cc66cc;\">4<\/span>;\r\n<span style=\"color: #808080; font-style: italic;\">\/\/ d = 5; \/\/ TypeError: Assignment to constant variable<\/span><\/pre>\n<\/div>\n<\/div>\n<\/div>\n<p><strong>\u041f\u0440\u0438\u043c\u0435\u0440 2: <code class=\"CodeInlined\">const<\/code> \u0432 \u0431\u043b\u043e\u043a\u0435 \u2014 \u0441\u043d\u0430\u0440\u0443\u0436\u0438 \u043d\u0435 \u0432\u0438\u0434\u0435\u043d<\/strong><\/p>\n<div class=\"CodeBlock CodeBlock_overflow_visible CodeBlock_highlight\">\n<div class=\"CodeBlock-StickyWrapper\">\n<div class=\"CodeBlock-Header\">\n<div class=\"CodeBlock-HeaderTitle\">js<\/div>\n<pre class=\"actionscript\" style=\"font-family: monospace; font-size: 14px;\"><span style=\"color: #b1b100;\">if<\/span> <span style=\"color: #66cc66;\">(<\/span><span style=\"color: #000000; font-weight: bold;\">true<\/span><span style=\"color: #66cc66;\">)<\/span> <span style=\"color: #66cc66;\">{<\/span>\r\n  const <span style=\"color: #0066cc;\">e<\/span> = <span style=\"color: #cc66cc;\">5<\/span>;\r\n<span style=\"color: #66cc66;\">}<\/span>\r\n<span style=\"color: #808080; font-style: italic;\">\/\/ console.log(e); \/\/ ReferenceError: e is not defined<\/span><\/pre>\n<\/div>\n<\/div>\n<\/div>\n<p><strong>\u041f\u0440\u0438\u043c\u0435\u0440 3: \u0441\u043e\u0434\u0435\u0440\u0436\u0438\u043c\u043e\u0435 \u043c\u0435\u043d\u044f\u0442\u044c \u043c\u043e\u0436\u043d\u043e, \u0441\u0441\u044b\u043b\u043a\u0443 \u2014 \u043d\u0435\u0442<\/strong><\/p>\n<div class=\"CodeBlock CodeBlock_overflow_visible CodeBlock_highlight\">\n<div class=\"CodeBlock-StickyWrapper\">\n<div class=\"CodeBlock-Header\">\n<div class=\"CodeBlock-HeaderTitle\">js<\/div>\n<pre class=\"actionscript\" style=\"font-family: monospace; font-size: 14px;\">const arr = <span style=\"color: #66cc66;\">[<\/span><span style=\"color: #cc66cc;\">1<\/span>, <span style=\"color: #cc66cc;\">2<\/span><span style=\"color: #66cc66;\">]<\/span>;\r\narr.<span style=\"color: #0066cc;\">push<\/span><span style=\"color: #66cc66;\">(<\/span><span style=\"color: #cc66cc;\">3<\/span><span style=\"color: #66cc66;\">)<\/span>;      <span style=\"color: #808080; font-style: italic;\">\/\/ \u043e\u043a: [1, 2, 3]<\/span>\r\n<span style=\"color: #808080; font-style: italic;\">\/\/ arr = [4, 5];   \/\/ \u043e\u0448\u0438\u0431\u043a\u0430<\/span>\r\n\u00a0\r\nconst obj = <span style=\"color: #66cc66;\">{<\/span> <span style=\"color: #0066cc;\">name<\/span>: <span style=\"color: #ff0000;\">'test'<\/span> <span style=\"color: #66cc66;\">}<\/span>;\r\nobj.<span style=\"color: #0066cc;\">name<\/span> = <span style=\"color: #ff0000;\">'new'<\/span>;  <span style=\"color: #808080; font-style: italic;\">\/\/ \u043e\u043a<\/span>\r\n<span style=\"color: #808080; font-style: italic;\">\/\/ obj = {};        \/\/ \u043e\u0448\u0438\u0431\u043a\u0430<\/span><\/pre>\n<\/div>\n<\/div>\n<\/div>\n<hr \/>\n<h2>\u0413\u0434\u0435 \u0447\u0430\u0449\u0435 \u0432\u0441\u0435\u0433\u043e \u0441\u043b\u0443\u0447\u0430\u044e\u0442\u0441\u044f \u043f\u0440\u043e\u0431\u043b\u0435\u043c\u044b<\/h2>\n<ul>\n<li data-value=\"\" data-shift=\"0\"><code class=\"CodeInlined\">var<\/code> \u0432 \u0446\u0438\u043a\u043b\u0435: \u0441\u0447\u0451\u0442\u0447\u0438\u043a \u043e\u0441\u0442\u0430\u0451\u0442\u0441\u044f \u0441\u043d\u0430\u0440\u0443\u0436\u0438 \u0438 \u0441\u043b\u0443\u0447\u0430\u0439\u043d\u043e \u0432\u043b\u0438\u044f\u0435\u0442 \u043d\u0430 \u0434\u0430\u043b\u044c\u043d\u0435\u0439\u0448\u0438\u0439 \u043a\u043e\u0434.<\/li>\n<li data-value=\"\" data-shift=\"0\">\u041e\u0431\u0440\u0430\u0449\u0435\u043d\u0438\u0435 \u043a \u043f\u0435\u0440\u0435\u043c\u0435\u043d\u043d\u043e\u0439 \u0434\u043e \u043e\u0431\u044a\u044f\u0432\u043b\u0435\u043d\u0438\u044f: \u0441 <code class=\"CodeInlined\">var<\/code> \u043f\u043e\u043b\u0443\u0447\u0430\u0435\u0448\u044c <code class=\"CodeInlined\">undefined<\/code> \u0438 \u0434\u043e\u043b\u0433\u043e \u0438\u0449\u0435\u0448\u044c \u043e\u0448\u0438\u0431\u043a\u0443; \u0441 <code class=\"CodeInlined\">let\/const<\/code> \u0441\u0440\u0430\u0437\u0443 \u043f\u0430\u0434\u0430\u0435\u0442 \u0441 \u043f\u043e\u043d\u044f\u0442\u043d\u043e\u0439 \u043e\u0448\u0438\u0431\u043a\u043e\u0439.<\/li>\n<li data-value=\"\" data-shift=\"0\">\u041f\u043e\u0432\u0442\u043e\u0440\u043d\u043e\u0435 \u043e\u0431\u044a\u044f\u0432\u043b\u0435\u043d\u0438\u0435: <code class=\"CodeInlined\">var<\/code> \u0442\u0438\u0445\u043e \u043f\u0435\u0440\u0435\u0437\u0430\u043f\u0438\u0448\u0435\u0442 \u0437\u043d\u0430\u0447\u0435\u043d\u0438\u0435, <code class=\"CodeInlined\">let\/const<\/code> \u043d\u0435 \u0434\u0430\u0441\u0442 \u044d\u0442\u043e\u0433\u043e \u0441\u0434\u0435\u043b\u0430\u0442\u044c.<\/li>\n<li data-value=\"\" data-shift=\"0\">\u041e\u0436\u0438\u0434\u0430\u043d\u0438\u0435, \u0447\u0442\u043e <code class=\"CodeInlined\">const<\/code> \u0434\u0435\u043b\u0430\u0435\u0442 \u043e\u0431\u044a\u0435\u043a\u0442 \u00ab\u043d\u0435\u0438\u0437\u043c\u0435\u043d\u044f\u0435\u043c\u044b\u043c\u00bb: \u043d\u0430 \u0434\u0435\u043b\u0435 \u043e\u043d \u0437\u0430\u0449\u0438\u0449\u0430\u0435\u0442 \u0442\u043e\u043b\u044c\u043a\u043e \u0441\u0441\u044b\u043b\u043a\u0443, \u0430 \u043d\u0435 \u0441\u043e\u0434\u0435\u0440\u0436\u0438\u043c\u043e\u0435.<\/li>\n<\/ul>\n","protected":false},"excerpt":{"rendered":"<p>\u041e\u0431\u043b\u0430\u0441\u0442\u044c \u0432\u0438\u0434\u0438\u043c\u043e\u0441\u0442\u0438 \u0433\u043e\u0432\u043e\u0440\u0438\u0442, \u0433\u0434\u0435 \u0432 \u043a\u043e\u0434\u0435 \u043f\u0435\u0440\u0435\u043c\u0435\u043d\u043d\u0430\u044f \u00ab\u0436\u0438\u0432\u0451\u0442\u00bb \u0438 \u0433\u0434\u0435 \u0435\u0451 \u043c\u043e\u0436\u043d\u043e \u0438\u0441\u043f\u043e\u043b\u044c\u0437\u043e\u0432\u0430\u0442\u044c. \u0415\u0441\u043b\u0438 \u043d\u0435 \u0443\u0447\u0438\u0442\u044b\u0432\u0430\u0442\u044c \u043f\u0440\u0430\u0432\u0438\u043b\u0430 \u0434\u043b\u044f var\/let\/const, \u043a\u043e\u0434 \u0431\u0443\u0434\u0435\u0442 \u0432\u044b\u0434\u0430\u0432\u0430\u0442\u044c \u0441\u0442\u0440\u0430\u043d\u043d\u044b\u0435 \u0437\u043d\u0430\u0447\u0435\u043d\u0438\u044f \u0438\u043b\u0438 \u043f\u0430\u0434\u0430\u0442\u044c \u0441 \u043e\u0448\u0438\u0431\u043a\u0430\u043c\u0438. \u0414\u0430\u043b\u044c\u0448\u0435 \u2014 \u0442\u043e\u043b\u044c\u043a\u043e \u0444\u0430\u043a\u0442\u044b \u0438 \u043f\u0440\u0438\u043c\u0435\u0440\u044b, \u043a\u043e\u0442\u043e\u0440\u044b\u0435 \u043c\u043e\u0436\u043d\u043e \u0441\u0440\u0430\u0437\u0443 \u043f\u0440\u043e\u0432\u0435\u0440\u0438\u0442\u044c. var: \u0436\u0438\u0432\u0451\u0442 \u043f\u043e \u0444\u0443\u043d\u043a\u0446\u0438\u0438, \u0432\u0441\u043f\u043b\u044b\u0432\u0430\u0435\u0442, \u0440\u0430\u0437\u0440\u0435\u0448\u0430\u0435\u0442 \u043f\u043e\u0432\u0442\u043e\u0440 \u0427\u0442\u043e \u044d\u0442\u043e \u0437\u043d\u0430\u0447\u0438\u0442 \u043d\u0430 \u043f\u0440\u0430\u043a\u0442\u0438\u043a\u0435: \u0412\u0438\u0434\u0435\u043d \u0432\u043e \u0432\u0441\u0435\u0439 \u0444\u0443\u043d\u043a\u0446\u0438\u0438, \u0431\u043b\u043e\u043a [&hellip;]<\/p>\n","protected":false},"author":9194254,"featured_media":135289,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[463],"tags":[],"class_list":["post-135288","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-javascript"],"views":9,"_links":{"self":[{"href":"https:\/\/rcl-radio.ru\/index.php?rest_route=\/wp\/v2\/posts\/135288","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/rcl-radio.ru\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/rcl-radio.ru\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/rcl-radio.ru\/index.php?rest_route=\/wp\/v2\/users\/9194254"}],"replies":[{"embeddable":true,"href":"https:\/\/rcl-radio.ru\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=135288"}],"version-history":[{"count":1,"href":"https:\/\/rcl-radio.ru\/index.php?rest_route=\/wp\/v2\/posts\/135288\/revisions"}],"predecessor-version":[{"id":135290,"href":"https:\/\/rcl-radio.ru\/index.php?rest_route=\/wp\/v2\/posts\/135288\/revisions\/135290"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/rcl-radio.ru\/index.php?rest_route=\/wp\/v2\/media\/135289"}],"wp:attachment":[{"href":"https:\/\/rcl-radio.ru\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=135288"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/rcl-radio.ru\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=135288"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/rcl-radio.ru\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=135288"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}